banjir jakarta

22Jan13

banjir jkt - bunderan hi

foto: The Jakarta Globe

tulisan di bawah ini didapat dari sebuah milis yang saya ikuti, dan mungkin juga beredar pada milis-milis yang lain. isi tulisannya bisa dibaca seperti sebuah “rangkuman” dari berbagai diskusi, berisikan berbagai aspek yang perlu dihadapi dan diperbaiki dalam mengelola air dan banjir. tentu saja tulisan ini bukan sekedar rangkuman karena didukung oleh data dan sumber yang melengkapi kedalaman analisa. reposting disini sebagai pengingat dan supaya lebih mudah saya mencarinya pada masa mendatang. mohon ijin kepada Jan T.L. Yap untuk meletakkan tulisannya disini.

Flood Management in Jakarta

Causes and Mitigation

A Contribution to the Policy Dialogue and Analysis

Balai Kota DKI Jakarta

January 22, 2013

Jan T.L. Yap

Lead Capacity Building Advisor

World Bank Jakarta Office

 

Introduction 

1. The Greater Jakarta Region is the nation’s economic and political powerhouse. Jakarta is one of the largest metropolises of Asia, and its economy is thriving and has recovered fast from the Financial Crisis. Although most other Asian cities are affected by local inundations, Jakarta has a history of vulnerability to floods, and as suggested, this situation will worsen unless more coordinated action is taken.

2. Both the 2002 and the 2007 flood paralyzed the city as well as Tangerang and Bekasi for over a week. Initial assessment in 2007 was estimated to reach Rp 1.8 trillion (US$ 200 million) and Rp 3.4 trillion (US$ 378 million) in damages and financial losses respectively (Paskah Suzetta, previous Chairman of Bappenas). These were not taking into account other economic, social and intangible losses (e.g. value of post-flood morbidity, lost travel time, unemployment, loss of property value, etc.) The 2002 flood was calculated to have caused a loss of about Rp 5.4 trillion (US$ 600 mln) in direct damages (mostly repairs) and Rp 4.5 trillion (US$ 500 mln) in economic losses. The economic losses are probably much higher and include the fact that all businesses lost working time and revenue, children could not attend school, and diseases and a poorly functioning communication cut productivity. Moreover, the city’s efforts to attract investment, and project an image of leadership nationally and internationally, were seriously damaged.

Need for Paradigm Shift in Flood Management 

3. Floods is not necessarily a problem as such, and do not always lead to situations which require development of capital-intensive flood protection infrastructure. It is a perfectly natural phenomenon in terms of probability of occurrence and should be approached following a risk management process.

4. Hydrologists, hydraulic & civil engineers played an important, if not dominant, role in flood protection, control and management. Engineers were and are de facto the decision-makers in case of flooding. Their technological approach in solving flood problems was almost never contested. Flood “Problem Solving are always made from hydraulic & civil engineering point of view.

5. The traditional approach is mainly Problem driven & Symptom combatment only; Reactive rather than proactive practices. A Project approach: solution seems self-evident without giving any thought to the impacts, largely relied on Structural Measures, ad-hoc & essentially mono-disciplinary, thinking in engineering solutions, and not in options or concepts. Rather than mitigating flood risk we largely succeeded in only shifting the flood problem spatially & temporarily. We fail to learn from past and continue to look for engineering solution by thinking that with engineering structures we are in control of the flood and hence, we are able to solve the flood problem.

6. Experiences and lessons learned from floods all over the world suggest that:

- Many flood problems today can be derived from “engineering solutions” in the past and uncontrolled urban and regional development;

- Disasters from flooding are the result of a random act of nature combined with poor risk management, uncontrolled development and mis-management of natural resources. Flood disasters are now increasingly being seen as the outcome of cumulative risk processes rooted in poor land-use practices, ill-conceived development projects, lack of rules and guidelines, absence or inconsistent law enforcement, etc.

- Floods can not be fully controlled, it should be accepted as a permanent fact of life;

- There is no “optimal” solution. Terms as “acceptable” solution or “the best compromise” indicate that there are other stakeholders involved in the decision making process. Usually there are many equally bad solutions and the exercise is to select from these bad solutions or to find compromises;

- Today Engineers are not the sole decision-makers anymore. They are a supporting group for the political decision makers;

- There is no such thing as “flood free”.

7. Flood protection efforts are attempts to mitigate flood damage. The populations should be made aware that it is impossible to protect them against the risk of flood; Make them understand the meaning of risk, that the risk of flood is real and it is always there to strike at anytime;

8. Citizens should be informed on the consequences of a flood. They must be made aware of and prepared for this risk, the unknown.

- The Causes of the Flooding in Jakarta

- Technical causes

- Maintenance

9. The most important cause is lack Operation and Maintenance (O&M) for the river and drainage system. Years of neglect in maintenance, and improper operation of control structures have resulted in siltation of the rivers and drains, clogging by solid waste, damage to drain pumps, etc. The discharge capacity of the drainage system (both that at macro- and micro-level) has reduced, sometimes to 30% of the required or design capacity.

10. The issue of sustainability of any design standard is a major problem where no agency accepts or is allocated operational responsibility for maintenance and/or inadequate Operation and Maintenance (O&M) funding is provided. Maintenance neglect and lack of a sustainable fiscal framework for O&M is as large a cause of flooding through under-capacity as any physical or land-use control reason.

11. Limited coverage of solid waste collection services. At present, the Cleaning Department of DKI Jakarta collects less than 40% of solid waste that is generated within its boundaries. In the absence of alternative options for waste disposal, the remainder is discarded in uncontrolled dumpsites or into the city’s canals and lakes, thereby clogging floodways and drains.

12. Insufficient funding for operations and maintenance. Actual O&M budgets of MPW and DPU-DKI are substantially lower than budgets required to properly maintain the infrastructure (in 2002, NEDECO estimated that spending by DKI on routine maintenance was less than 10% of the required amount).

Spatial Planning

13. The reduction of open space and green area also affected the drainage flow pattern in DKI Jakarta. The direct runoff within the city is much higher than originally estimated for the design of the drainage system. In addition, the drainage system itself is very much affected by land subsidence leading to low and ineffective performance of the system.

14. Encroachment of the riverbanks adds to increased risk of flooding and flood damage. Construction of structures in the flood plain and crossing the rivers and drainage system have increased water levels during floods and exposed these assets to increased risk of damage during flood periods.

15. Lack of enforcement of spatial plans and building regulations. Regulation of buildings according to a spatial plan (based on floodplain management) is not carried out or enforced. Furthermore, new housing developments within and around Jakarta have not been regulated by a spatial plan designed to ensure retention of adequate green areas that would have stored and absorbed normal flood runoff. The increased paving resulting from extensive build-up of housing and roads further reduces soil capacity to store rainfall and exacerbates runoff within the city. The lack of enforcement of building regulations also contributes the land subsidence, riverbank encroachment, and the rapid disappearance of waduk.

Urban Drainage System

16. The flood problem is not a new problem. It is caused by numerous, well-known shortcomings in how the city prepares itself for these events. Only a small part of the problem is to be attributed to nature: very extreme weather and very intensive rain that occur only once every 100 or 200 years can create situations that probably no city drainage system can accommodate. However, the 2002 and 2007 floods were arguably caused by rainfall that occurs on the average every 5 year (Return Period of 5 years), and this should be easy to accommodate. The original city drainage system was designed to accommodate river discharges that occur once every 25 or even 50 years (Probability of Flood Occurrence).

17. But now the city’s infrastructure already fails under much less demanding conditions. DKI and the Provinces and Kabupaten in the Greater Jakarta Region appear to have several weaknesses in planning and management: in river basin management, design and operation & maintenance (O&M) of the metropolitan drainage infrastructure, urban planning and land use management, and also in the behavior of the public that fails to value the city’s drainage system.

18. The intensity and duration of the rainfall in the wet season varies from year to year, but their occurrence can be well predicted by statistical analysis. The rains that caused the floods in 1996, 2002 and 2007 have an average return period of 5 to 6 years. But they created a flooding extent that was supposed to happen only once in 20 years. Thus, it is particularly worrying that in January 2013, already 6 years later, a new major flood has occurred during the beginning of the rainy season. Many agencies predicted that floods during the remaining part of the month of January 2013 and early February may be of even greater size.

19. Due to watershed degradation and urbanisation, the flood peaks and damages may continue to increase while internal and main drain outflow congestion becomes worse, as outlined earlier. While many rightly point to watershed degradation as a major contributing factor to flooding, field conditions seem to imply that diversion of flood flows out of the Ciliwung River near Bogor to the Cisadane River may not greatly reduce flood damage from rainfall and poor internal drainage within the Jakarta urban area.

20. Lack of enforcement of forest law and regulations. After many years of illegal logging, most forests in the Ciliwung River Basin have disappeared. A planned reforestation program, which would mitigate erosion along the river and its tributaries, has not been implemented.

21. Rapid Obsolescence of Flood Control Protection Standards. One of the major questions that arise is the frequency of the present flooding: is this a 10 year average return period event, a 25-year event or even a less infrequent event? It would seem that the design capacity of part of the present major flood and drainage network was designed for a 25-year event: if this is so, this design standard is wholly inadequate for a major high value “Central Business District” or land use. It must be realized that, even if the amount and intensity of a 5-year rainstorm does not change, the rapid degradation of the upper watershed (as well as urbanization) results in greater flood peaks: i.e. 5-year storm gradually becomes a 25-year event!

22. Although, a Western Diversion Canal (West Banjir Canal) was constructed in 1919 and the Cengkareng Floodway in 1982, the growth of the city has greatly outstripped its service area. Furthermore, these floodways, rivers and major drains have a reduced capacity due to a combination of river bed aggradations, siltation and solid waste dumping. Floodway encroachment through unauthorised development and squatting further reduce capacity and increase the physical, social and economic costs of flooding. Thus a combination of physical factors, neglect and, inaction have contributed to duration, frequency and spatial extent of flooding in the DKI Jakarta area.

23. Recently, an Eastern Diversion Canal (East Banjir Canal) was constructed to protect certain areas in the North-Eastern part of Jakarta. This may lead to reduction of flood damages in those areas. Maintaining its service level is key. Performance of this new floodway during the recent floods in January

2013 is still to be assessed. This assessment might demonstrate the effectiveness of the huge investments made and how far it is able to reduce flood damage as compared to the case without existence of this floodway.

Land subsidence

24. Rapid urbanization along with severe uncontrolled and over-extraction of groundwater in areas not connected to the municipality water supply distribution system leads to continuous subsidence of the ground surface. Over pumping of the shallow and deep aquifers underlying the area causes land subsidence that, in turn, exacerbates local flooding due to poor and impeded internal drainage and reduction of outlet capacity. Because of land subsidence in the northern part of Jakarta, bridges and pipelines of public utilities (PLN, PGN, PDAM) are too low and obstruct the water flow, severely reducing the discharge capacity of the system.

25. Lack of enforcement of regulations on groundwater abstraction. DKI prohibits groundwater abstraction without a license. In practice, this regulation is not enforced.

Flooding from the Sea

26. Whenever the Java Sea rises during the monthly lunar tidal cycle, water rushes inland and inundates parts of Muara Baru, which like 40 percent of Jakarta, and most of North Jakarta, lies below sea level. Within 10 years from now it will be at the mercy of an upswing in the tides unless city and national government officials finally do something about it. International experts predict tides will surge far inland without a proper sea defence system in place. The areas of the city most vulnerable to tidal flooding are Muara Baru, Muara Karang, Penjaringan, Pademangan, Tanjung Priok, Pluit, Koja and Kapuk Muara. Most are industrial areas surrounded by densely populated villages.

27. Astronomic tidal fluctuation in the Bay of Jakarta has an 18.6 year cycle. On November 26, 2007 the astronomic cycle peaked in conjunction with annual spring tides and resulted in damaging floods from the sea that were largely unexpected. So far, it was assumed by the local government and community that Jakarta was only threatened by rain induced floods. A recent study on Flood Hazard Mapping clearly showed that from 2007 Jakarta will be severely threatened by floods from the sea as well. Although the astronomic tidal cycle is retreating in the coming years after reaching its peak in 2007, the inundations from the sea will continue because of the ongoing land subsidence in the northern part of the city. Moreover, flooding will still occur when rain induced floods coincide with high spring tides. The tidal cycle will start rising again in about 4 years from now and tidal floods will become particularly severe again. This extreme tide is also described in “Tidal Dynamics” by Fergus J. Wood (1986) as “Extreme Proxigean Spring Tides” that may cause severe flooding along the coast. The peak of the next tidal cycle is expected in 2025 to occur.

28. Continuous subsidence of the northern part of Jakarta combined with, and the expected rising limb of the astronomic tides over 4 years from now ultimately leading to the next Proxigean tidal period in 2025-2026, and the sea level rise as result of climate change, and changing rainfall pattern and intensity due to climate change, will cause disastrous flooding in North Jakarta. Although the predicted figures for the sea level rise in the Bay of Jakarta is still far from accurate, some allowance for this phenomenon should be taken into consideration. To protect the coastal area of DKI will require very large quantities of outfall pumping and huge low-lift pumping stations. These will increase costs and require failsafe and fully reliable operation.

Institutional causes

29. The basic challenge is the limited, if any, coordination between the different authorities, the absence of a proper metropolitan structure for O&M, and severely constrained O&M budgets. The Provincial Governments of West Java and Banten and the Kabupaten do not have incentives to take responsibility for flooding originating from the Upper Ciliwung watershed.

30. No coordination platform exists at which proper planning, operation and maintenance of the entire flood control system is coordinated between the different governments at regional and central levels. No clear agreement exists on tasks and responsibilities between the institutions.

31. Lack of coordination between authorities responsible for water resources management. No platform exists for the coordination of the planning, operation and maintenance of the entire flood control system among the various national and sub-national governments responsible for water resources management (including activities closely related thereto, such as solid waste management).

32. Lack of incentives for interregional coordination. At present, provinces, kabupaten and kota in upstream areas do not have financial or other incentives to mitigate floods that mainly affect citizens outside their jurisdictions.

33. There are no structural systems for annual thorough inspection of flood management infrastructure, flood preparation drills, and flood data collection (such as post-flood mapping). As Jabodetabek keeps growing, the flooding extent will irrevocably spread further. The flood warning and disaster management systems are not well developed and effectively operated.

34. Beneficiaries and stakeholders do not participate in the process of planning, implementation and O&M of the drainage and flood system.

35. Limited technical expertise. The organizations responsible for flood control systems in Greater Jakarta lack the technical expertise to manage these systems according to the standards needed for a metropolitan area of Jakarta’s size. At present, there are no structural systems for annual inspections of flood control systems, flood preparation drills, or collection of flood data (such as post-flood mapping). In addition, flood warning and disaster management systems are not well developed or effectively operated.

36. Absence of political leadership to address the above issues in integrated manner. This is perhaps the important constraint to the mitigation of Jakarta’s annual floods.

Water Governance and Integrity 

37. Good governance incorporates elements of participation, transparency and accountability. Accountability and participation are tools for ensuring transparency, honesty/integrity and reducing corruption. Many issues mentioned above can be attributed to weak application of Good Governance Principles and low levels of Integrity leading to low law enforcement and violations of government regulations;

38. Impacts of weak practices of water governance and integrity are:

- Impacts on economic efficiency.

- Impacts on social equity, cohesion and poverty reduction.

Impacts on environmental sustainability and health

39. Typical corruption practices in urban and flood programs and projects are among others:

- Influence project decision-making;

- Bribery for preferential treatment;

- Distortionary decision-making by collusion with leaders in selection and approval of plans, project-level site selection, equipment selection and procurement, construction supervision on quality of the infrastructure;

40. The main reason for failure of structures or embankment under normal operational conditions is poor quality of the structure. The reason of poor quality structures is mainly attributed to corruption during construction: bribery and fraud involving failure to build to specification, concealing substandard work materials, failure to complete works, etc.

41. As construction of water infrastructure involves complex, non-standard construction processes and methodologies that foster asymmetric information between clients and providers, it is perhaps unsurprising that construction is frequently seen as one of the most corrupt industries worldwide. Corruption in construction always aim to lower standards for construction supervision leading to sub-standard quality of the urban and flood management infrastructure.

42. There is a general tendency to build new infrastructure rather than to plan and implement proper maintenance of existing infrastructure. The decision whether to proceed with a new project or rehabilitate or upgrade existing infrastructure is itself prone to corruption as several decisions are involved. Despite the fact that maintenance is key to preserving the economic value of infrastructure and a necessary investment to arrive at the projected benefits that are projected during the feasibility study, there remain large incentives to build new infrastructure.

Options to Move Forward 

43. The key is to start managing flood prevention pro-actively rather than reactively. This means:

- Instead of paying for clean up after the event, investing resources to reduce the incidence and severity of flooding;

- Instead of only constructing new facilities and infrastructure, maximizing the performance of the existing infrastructure; and

- Encouraging co-operation and “win-win” solutions between the downstream and upstream regional governments.

44. The resolution of these challenges is the responsibility of the regional and national governments. No new policies are needed to achieve the above. What is needed, however, is a practical implementation strategy and stronger political support across the Greater Jakarta Region for implementing the existing policies and the strategy. This will require increasing local financial resources for the O&M of the infrastructure, and access to finance for new infrastructure investments.

45. All the necessary actions inside DKI, Tangerang and Bekasi are the sole responsibility of the respective governments; however, the control of the flood water entering from the upper catchments requires broader cooperation. In general, the regional nature of the floods and the drainage and economic interlinkages between these territories calls for deeper coordination. For example, Tangerang receives part of DKIโ€s drainage water. Although the C-C River Basin may become legally defined as a Nationally Strategic Basin (under the control of the Ministry of Public Works), effective action will require cooperation with all the Provinces and Kabupaten as only they can introduce and maintain land use regulations and maintain much of the local water infrastructure. Therefore, an effective intergovernmental institution to coordinate planning, implementing and enforcing Greater Jakarta Region and C-C Basin flood management would be essential to the flood mitigation.

46. Any structural solution and adjustment of the physical infrastructure to appropriate protection levels will require careful economic, financial and social trade-offs. If financial and social constraints require a lower standard, then an enforceable system of non-structural flood control measures (flood insurance, flood-proofing and flood zoning) which, to date have been inconceivable and/or for which no appropriate urban and regional institution exists!

47. Introduction the concept of Sustainable Urban Drainage System (SUDS). SUDS make use of the landscape and the urban spatial plan to imitate natural drainage by source control and drainage management. Consider enforcement of SUDS in new development and use of SUDS elements in built-up areas.

48. Introduction of Good Water Governance and Integrity practices and application of integrity tools are essential initiatives in the holistic approach to Integrated Flood Management. It should cover the whole project cycle from initial planning, procurement and construction, and operation and maintenance. This goes hand-in-hand with strict law enforcement at all levels.

Critical Steps to be taken

Proposed Critical Actions that need to be taken within 1 year and activities in the short- and long term are presented below.

Critical actions (0 – 1 year)

1. Extend Emergency Assistance in the aftermath of the recent floods in January 2013, to affected victims of the flood.

2. Prepare for possible more floods to come:

- National and provincial government agencies and emergency and flood relief units;

- The Civil Society vulnerable to inundations to organise the community to embrace and prepare themselves for evacuation and damage mitigation.

3. Repair damaged strategic infrastructure.

4. Revive the dialogue between PU, DKI, West Java and Banten provinces, and neighboring Kabupatens, initiated and coordinated by the National Water Council, and prepare action plan to set up a Flood Coordinating Body;

5. Prepare a road map based on previous studies, existing laws and by-laws, e.g. UU7/2004 for an Integrated Action oriented sustained flood management plan with active participation of the public and private stakeholders;

6. Flood proofing of critical and vital facilities (drainage pumping stations, water supply plants, power, communication, access roads, hospitals, emergency centers, etc.);

7. Assess flood damage of the floods in 2013 and prepare related flood damage maps;

8. Restore discharge capacities of selected major and micro internal drainage and main drainage systems by dredging outlets of critical rivers/main drains, such as the Western and Cengkareng Floodways;

9. Initiate a strengthening program for the National and Provincial Flood Disaster Agencies (Bakornas/Satkorlak ) or in management of flood disasters (Rapid response); and

10. Introduce the new concept of SUDS for application in iurban drainage planning and management;

11. Initiate Good Water Governance practices and application of Integrity tools within the relevant agencies.

Short term (1 – 3 years)

12. Continue and expand the activities under 3, 4, 5 and 6;

13. Strengthen the data collection on rainfall, river/drain hydrology and flood damage mapping;

14. Improve O&M performance through institution strengthening, in particular O&M budgeting system;

15. Strengthen planning and design units of DKI in urban drainage and flood management;

16. Prepare flood risk maps using updated topographical maps, in particularly areas experiencing subsidence due to uncontrolled groundwater pumping;

17. Prepare and implement an effective and sustainable and strategic solid waste management program;

18. Continue and accelerate improvement of water supply services and coverage in critical areas to mitigate land subsidence due to over-pumping;

19. Develop a viable and socially sustainable Urban Plan for slum and squatter relocation out of the floodway areas, including the coastal areas;

20. Develop and implement a non-structural flood management program (floodplain zoning, insurance and flood-proofing, warning and flood relief) with strong institutions for enforceable regulatory arrangement with priority for the needs of the highly vulnerable poor population and its informal sector enterprises;

21. Improve the water management and catchments protection around DKI, incl. updating the Basin Plan for Ciliwung-Cisadane Basin, flood routing plan and restore retaining capacity in the upper catchments;

22. Repair, rehabilitate and upgrade flood gates and drains to improve operation procedures and arrangements;

23. Repair, upgrade and refurbish existing pumping stations and appurtenant structures and improve O&M of related flood retention ponds, including sustainable O&M funding;

24. Improve road drainage systems and works to alleviate flooding from main highways and toll roads.

Long term (2 – 7 years)

25. A long-term and sustainable Watershed Stabilization Program based on a “zero-growth” policy in the Puncak area coupled with an intensive structural and non-structural soil conservation program in the upland areas (with special attention to erosion along steep roads);

26. A long-term and sustainable Watershed Stabilization Program in the upper catchments of the Ciliwung river and other large rivers, such as the Pesanggrahan, Angke, Cipinang/Kali Baru and Sunter;

27. A program to improve the many small ponds that are in the lower catchments area to act as detention basins for sediment and flood flows, including a viable arrangement prevent their encroachment;

28. Undertake a sustainable program of dredging the major rivers on a periodic basis;

29. Improve the functioning of internal macro and minor drains through a sustainable O&M program, and pumped or gravity outfalls that will operate reliably under extreme flood flow conditions in the recipient major drains and rivers;

30. For high-value real estate in low-lying areas, develop a “polder” approach with pumped outfalls whose O&M costs are borne by beneficiaries;

31. Assess the performance of the water management system of existing polder systems (required and updated storage capacity vs. pump capacity)

32. Institute a strong and enforceable regulatory system for managing groundwater abstraction and its reduction through a viable incentive approach, including increasing service coverage of water supply;

33. Institute an effective and sustainable flood preparedness, flood fighting and post-flood relief program under the existing Disaster Management Agencies in the provinces;

34. Institute a government policy on beneficiary cost recovery which ensures full or partial fiscal sustainability for O&M (including pumping costs) and rehabilitation;

35. Introduce a flood insurance scheme for private sector enterprises in the potentially affected areas;

36. Ensure appropriate involvement of civil society and NGOs in the institutional and implementation arrangements;

37. Consider setting up a JABODETABEK/ regional Flood and Drainage Authority made up of the agencies and governments who would have management authority over water resources planning, operation, implementation, O&M and financing.

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2 Responses to “banjir jakarta”

  1. 1 theo

    Jakarta terlihat coklat saat itu, semoga kejadian itu tidak terlualang lagi. suskses lah untuk pak jokowi dalam membenahi jakarta. great artcile, regards.

    GPS Tracking

    • 2 Kom

      Strategy yg ditawarkan sangat menarik. Perlu diinfokan kpd para pengamabil keputusan. Dan mari kita “mengawalnya”. salam


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